1. Field of the Invention
This invention relates generally to vibration damping mounts for shaft bearings and, more particularly, to an improvement in squeeze film damping type mounts.
2. Description of the Prior Art
In devices such as gas turbine engines where shaft speeds may exceed several thousand revolutions per minute, shaft bearing mounts typically include provision for damping transverse vibrations or oscillations of the shaft. In squeeze film damping type mounts an annulus of oil between the shaft bearing and its supporting structure distorts as the shaft vibrates. The viscosity of the oil film resists such distortion and, consequently, the oil develops a force opposing vibratory displacement, the opposing force functioning to damp the vibrations of the shaft. In addition, some squeeze film damping type bearing mounts include springs which bear the weight of the shaft to maintain the latter aligned on its axis of rotation when at rest. In such mounts, the degree of damping available is generally proportional to the surface area of the concentric cylindrical surfaces defining the squeeze film annulus. Increasing the surface area by increasing the axial length of the surfaces has been the typical method of obtaining increased damping. A squeeze film damping type bearing mount according to this invention has resilient centering capability and increased damping capability without a corresponding increase in length.